Characterization of dual beam optical tweezers system using a novel detection approach

Huilas Sehgal, Tanuj Aggarwal, Murti Salapaka

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


Characterization of optical tweezer system involves determining the stiffness coefficient of the trap and the range in which it behaves as a linear spring. This is often done by calculating the power spectrum of the fluctuations of the trapped bead observed on a photodetector. The detection process entails observing the deflection of either the same trapping beam or a different laser beam of very low power. We present a new approach where a laser beam from a source is split into s- and p- polarizations where s-polarization is used for trapping and p-polarization for detection. We also analyze and experimentally verify the effect of the detection beam on the trap dynamics. We further explain how to incorporate the effect of a strong detection beam, capable of trapping beads, in the photodetector calibration in a dual beam trap scenario. The novel detection method and the associated modelling sets the stage for the application of modern control approach.

Original languageEnglish (US)
Title of host publicationProceedings of the 2007 American Control Conference, ACC
Number of pages6
StatePublished - Dec 1 2007
Event2007 American Control Conference, ACC - New York, NY, United States
Duration: Jul 9 2007Jul 13 2007

Publication series

NameProceedings of the American Control Conference
ISSN (Print)0743-1619


Other2007 American Control Conference, ACC
CountryUnited States
CityNew York, NY

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